1. Field of the Invention
The present invention relates to a method and apparatus for chromatography mass spectrometry.
2. Background Art
When a sample constituted by a plurality of components is measured by a liquid chromatography-mass spectrometry using a combination of a separating instrument and a mass spectrometer, the sample components are successively observed as ions. By this liquid chromatography-mass spectrometry, a three-dimensional data in which mass spectra consisting of the ion intensity with respect to the mass-to-charge ratio are accumulated at certain times (so-called retention times) can be obtained. Trials have been made by using such data for quantitative comparative analysis of components contained in different samples. In many cases, however, the retention times of individual components are not reproduced. There is a demand for a method of establishing correspondences between identical components between samples.
Methods for correcting retention times so that identical components have the same retention times have been devised on the assumption that even if the retention times of components vary, the order in which the components are observed is not changed. For example, patent document 1 and a non-patent document 1 disclose methods of establishing correspondences between retention times by considering the fact that similar mass spectra are produced from components identical to each other. In the methods disclosed in patent document 1 and a non-patent document 1, similarity between samples are computed with respect to mass spectra obtained by measuring the samples. However, when individual sample components vary under circumstances where the separating effect of chromatography is not sufficiently high and where ions derived from a plurality of components are observed in mass spectra, the mass spectra do not necessarily coincide with each other with accuracy. Dynamic programming is then used to successively obtain the correspondence relationships between retention times through observation of sample components.
[Patent document 1] WO 2004/090526 A1
[Non-patent document 1] Masaya Ono, Miki Shiashige, Kazufumi Honda, Tomohiro Isobe, Hideya Kuwabara, Hirotaka Matsuzuki, Setsuo, Hirohashi, and Tesshi Yamada “Label-free Quantitative Proteomics Using Large Peptide Data Sets Generated by Nanoflow Liquid Chromatography and Mass Spectrometry” Mol. Cell. Proteomics, 5: 1338-1347 (2006).